This section introduces aspects that may help facilitate a better understanding of the invention(s). Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art.
Nowadays, various digital devices for presenting digital content are becoming more popular, such as mobile phone, PDA (Personal Digital Assistant), Tablet PC (Personal Computer), media player, or the like. The digital form of content makes it more easily to be distributed and propagated through network. The digital content may be, for example, music, video, image, game. The owners of content copyrights have gradually allayed concerns over unauthorized copying and distribution over a network, and they have now licensed content providers to copy and distribute digital versions of their copyrighted music, videos, images, games, etc. over the internet.
Content providers may like to add Digital Rights Management (DRM) to their authorized content, for example, enabling access control and preventing illegal distribution of the content. A typical content access scenario in the real world is location-based (or spatially-constrained) experience or consumption. For example, a user could freely access content within a specific place (e.g., experience store, hotel, coffee café, bar, club), with or without a fee; the user could not access the content any more when he or she leaves the place.
There are many example scenarios where a location-based access management may be desired. As an example, an experience store (for content and/or device) could allow a user to download and try a full-version of a paid mobile game when and only when the user is detected to be inside the store. As another example, a multimedia experience store could allow a user to download and feel vividly the effects of ringtones, wallpapers or screensavers on his or her own mobile devices before payment. Of course, such free experience is only provided when the user is in the store and the trial content must become inaccessible when the user goes out. As a further example, a recreation spot could provide customers free or almost free content consumption as a kind of attractive supplement to its service. For example, in a coffee café, a user could freely download and listen to selected songs of his or her preference when enjoying coffee. In a hotel, a user could download songs or movies to his or her mobile device and play them when/wherever he or she likes from within the hotel, e.g., from a lobby, a swimming pool, a sauna, a hot spring spot.
There are several known solutions for those above scenarios where a location-based access management is desired. One solution is to use on-site devices. A user can experience a piece of content using a device that is provided by the place, such as trying a mobile phone in a retail store with a little preloaded content. However, users are constrained to use a limited number of devices that are available in the place. The waiting time for a device may be long if a large number of customers are waiting. Also, the place may need to pay a considerable amount of maintenance charge for the devices that it provides.
Another solution is in-memory content delivery in a streaming manner. Specifically, all or part content is streamed into the random access memory (RAM) of a user's mobile device continuously over time for viewing and playing. With such solution, a user could use his or her own personal device. However, the content is disallowed to be permanently stored. Thus, the user has to re-download the content again and again if it is removed from the RAM. The repetitive download will consume a large amount of network bandwidth and burden the content server. Further, content providers may be worried about potential copyright infringement via network snooping due to transmission of plain, unencrypted content.